Method of optical brightening

ABSTRACT

THIS INVENTION RELATES TO METHODS FOR OPTICAL BRIGHTENING UTILIZING CERTAIN NOVEL 2-STYRYLOXAZOLE COMPOUNDS. THE METHODS ARE PARTICULARLY APPLICABLE TO ORGANIC FLBROUS MATERIALS ESPECIALLY OF SYNTHETIC NATURE, AQUEOUS DISPERSIONS OF THE COMPOUNDS, TOGETHER WITH DISPERSING AIDS BEING SUITABLE. THE SAID COMPOUNDS MAY BE EITHER BENZOXAZOLES OR NAPHTHOXAZOLES AND VARIOUS SUBSTITUENTS MAY BE PRESENT IN THEIR MOLECULAR STRUCTURES. SOME OF THE COMPOUNDS ARE FOUND TO BE ESPICALLY SUPERIOR AND CERTAIN FIBROUS MATERIALS ARE NOTABLY BENEFITED.

United States Patent Ofice Re. 27,031 Reissued Jan. 12, 1971 Matter enclosed in heavy brackets appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

ABSTRACT OF THE DISCLOSURE This invention relates to methods for optical brightening utilizing certain novel 2-styryloxazole compounds. The methods are particularly applicable to organic fibrous materials, especially of synthetic nature, aqueous dispersions of the compounds, together with dispersing aids being suitable. The said compounds may be either benzoxazoles or naphthoxazoles and various substituents may be present in their molecular structures. Some of the compounds are found to be especially superior and certain fibrous materials are notably benefited.

This application is a division of our prior application Ser. No. 220,904, now Patent No. 3,262,929.

This invention relates to methods of optical brightening utilizing novel Z-styryloxazole compounds.

It is an object of this invention to provide new and useful methods for optical brightening of organic fibrous materials.

The novel 2-styryloxazole compounds of this invention have the structure represented by the general formula:

wherein A is a member selected from the group consisting of substituted benzene rings and unsubstituted naphthalene ring, which is condensed with the oxazole ring, substitutes of said benzene rings being selected from the group consisting of alkyl-, aryl, and alkylene-groups, and R and R are selected from hydrogen, halogen, cyano group, carboxyl group and its ester residue, alkyl group and aryl group.

2-styryloxazole compounds were little known in the past, although, for example, 2-styrylbenzoxazole and 2- (4'-dimethylaminostyryl)-benzoxazole were found (D.M. Brown, A. R. Kon, J. Chem. Soc., 1948, 2147).

The present inventors have synthesized a number of 2- styryloxazole compounds to study precisely on their properties, and have found that the novel 2-styryloxazole compounds having the general Formula 1 exhibit a strong fluorescence and produce an excellent optical brightening effect when organic fibrous materials are treated with these novel compounds. That is, the novel Z-styryloxazole compounds are very useful substances as the optical brigntening agent for organic fibrous materials, particularly various man-made fibers, and light-fastness is excellent.

The novel Z-styryloxazole compounds of this invention can be prepared by condensation under dehydration of a Z-methyloxazole compound represented by the following general formula (wherein A is the same as that in the general Formula I), with a benzaldehyde derivative represented by the following general formula:

R III (wherein R and R are the same as those in the general Formula I).

Alternatively the compounds of this invention can be prepared by intra-molecular ring closure under dehydration of a novel cinnamic acid-(O-oxyaryl)-arnide derivative represented by general formula:

\/ H R n (wherein A, R and R are the same as those in the general Formula I).

The following compounds can be cited as examples of Q-methyloxazole compound of the general Formula 11 among the starting materials employed for preparing the novel 2-styryloxazole compounds of this invention:

Z-methylbenzoxazole 2,5-dimethylbenzoxazole 2,5 ,7-trimethylbenzoxazole 2-methyl-4,5-cyclotetramethylenebenzoxazole Z-Inethyl-S-ethylbenzoxazole Z-methyl-5-isopropy1benzoxazole Z-methyl-5-tert-butylbenzoxazole 2-methyl-5-phenylbenzoxazole 2-methyl-S-acetylaminobenzoxazole Z-methyl-a-naphthoxazole Z-methyl-fi-naphthoxazole and the like.

And also the following compounds can be cited as examples of benazldehyde derivative of the general Formula III among the starting materials:

The condensation reaction under dehydration of 2- methyloxazole compound of the general Formula II with benzaldehyde derivative of the general Formula Ill can 4-methyl-2aminophenol 4,6-dimethyl-2-aminophenol l0 4-e-thyl-2-aminophenol 4-phenyL2-aminophenol l-amino-2-naphthol Z-amino-l-naphthol and the like,

or their inorganic acid salts with cinnamic acid halogenide, for example,

cinnamic acid chloride 3-chlorocinnamic acid chloride 4-chlorocinnamic acid chloride 4-cyano-3 chlorocinnamic acid chloride according to a conventional method. The intra-modecular ring closure reaction under dehydration of cinnamic acid- (O-oxyaryD-amide thus obtained can be carried out in an inert organic solvent such as xylene, chloiobenzene, dichlorobenzene and the like by adding a dehydrating agent and causing a reaction by heating.

The examples of novel 2-styryl0xazole compounds of 15 this invention are shown in Table 1.

TABLE 1 Fluorescence No. Structural Formula Property and melting point in blenizene so u on 1 A 0\ Colorless needle-like crystals, lot-155 Violet.

CCH:HC Cl 2 0 Light yellow pillar-like crystals 196- D0.

/OCH:HC -CN N 3 0 Slightly yellow plate crystals 146-147 Do.

4 0 Light yellow pillar-like crystals 310 Do.

C-CH=HC -oN C*on=uc -GN II5CJ- o cn=11o co011 H;C

Colorless needle-like crystals, 14l-142 Do.

Liggt yellow noodle-like crystals, 221 Do.

Light yellow noodle-like crystals, 155- Do.

Light yellow needlelike crystals, 260- Blue.

Slightly yellow needle-like crystals, Blue-violet.

XVI-209 C.

TABLE 1Contlnued Fluorescence No. Structural Fonnula Property and melting point in benzene solution 10 O Sllverwhito flnkwlike crystals, 134- \"lnlnL 11 0 Light yellow needle-like crystals, 1S4 Bluei let,

/C--CH:HCCN N 12 0 Light yellow plIlar-llkr: crystals, 295- D c-cn=nc c OOH 01mmv 13 0\ Colorless flake-like crystals, 175476C Violet-blue,

C-CII=HCGN 14 l Colorlessfiake-llkecrystals, 12+125 c. Blue-violet,

CCH==HC- 15 A Slightly yallow lum-4m crystals, Blum C C H=H C 16 O Llght yellow pillar-like crystals, 12? (neon-blue.

123" c. I (l C H: H O l N 17 7 0 Cl Slightly yellow medlelike crystals, llluv-gnon.

158-169" 0. /ccn=11 06 L) N 18 0 Elm.

Light yellow flake-like crystals, 114- TABLE 1-Continued No. Structural Formula. Property and melting point Fluorescence in benzene solution 19 Yellow needle-like crystals, L'HHGU" C. Green-blue.

oon=nc ci U N 20 0 Light yellow pillar-like crystals, Violet-blue.

125-126" C. CCH=HC-F 21 O Greenish yellow pillar-like crystals, Blue-green.

C-CH:HC-Br U l N 22 -r 0 Light yellow flake-like erystuls, lL3- Violet-blue.

124C. c-cn=nc-cm [j t N 23 0 Yellow long flake-like crystals, Blue.

c-cn=nc--ooou N As shown in Table 1, the novel Z-styryloxazole com- TABLE 9 pounds of this invention have fluorescence of blue violet Compound Treatment Treatment Light to violet also q exceuflm infinity to orga lc FibcrMutcriuls COIlCUlltl'tlr temperatimes tmlu.) [astnuss fibrous materials from its aqueous dispersed y t m so 60 tionporcout turoCU.) that they are very useful for optical brightening of manmade fibers, particularly polyester, polyacrylonitrile, poly- Emmet: Q 2 120 45 4 amide, acetalized polyvinyl alcohol, polyolefin and cellugggggflg 3g 2g lose acetate fibers and their light fastness is remarkable. gigggjjj o,

' f Acetalized poly- For example, the compound No. 18 n Table is made vinylalcoholn M 45 3 mto aqueous dispersed system by using anionic surface Po]ypy'opylene Q1 45 active agent of alkylbenzene sulfonic acid type, and when the above-mentioned man-made fibers are treated in a treating bath which is prepared in such a way as the amount of this compound is 0.1% or 0.2% to the material to be treated, an excellent optical brightening effect can be obtained. The treating conditions and the light fastness (according to I18 L 10454959, Xenon light source) of man-made fibers in this case are shown in Table 2.

It is convenient to use a composition which in previously mixed with a surface active agent in order to treat 0 organic fibrous materials by using the compound of The process for preparing 2-styryloxazole compounds of this invention and the method of optical brightening of organic fibrous materials by using such compounds are illustrated by the following examples. Percents and parts herein are by weight.

EXAMPLE 1 2,5-dimethylbenzoxazole (14.7 parts), 4-carboxybenzaldehyde (15 parts) and zinc chloride (5 parts) are thoroughly mixed and are caused to react at 160-200 C. for 8 hours with stirring. The reactants are boiled and dissolved in methanol of 10 times volume. On cooling the methanol solution, S-methyl-Z-(4-carboxystyryl)-benzoxazole is precipitated as yellow crystals. When crystallized from ethanol containing glacial acetic acid, light yellow pillar-like crystals (M.P. 310 C.) are obtained.

EXAMPLE 2 2,5 dimethylbenzoxazole (14.7 parts), 4 cyano 3- chlorobenzaldehyde (18 parts) and zinc bromide (13 parts) are thoroughly mixed and are caused to reaction at 160 C. for 6 hours with stirring. In this case the water formed by the reaction is successively driven out of the reaction system. The reactants are boiled and dissolved in 50 parts of methanol. On cooling the methanol solution, 5 methyl-2-(4'-cyano-3chlorostyryl)-benzoxazole is precipitated as yellow crystals. When recrystallized from dimethyl formamide, light yellow needle-like crystals (M.P. 221 C.) are obtained.

EXAMPLE 3 2,5,7 trimethylbenzoxazole (16.1 parts), 4 cyanobenzaldehyde (13.1 parts) and zinc chloride (7 parts) are mixed thoroughly and are caused to react at 160-200" C. for 8 hours with stirring while the formed water is successively taken out of the reaction system. Then, the reactants are subjected to steam distillation and unreacted starting materials are distilled out. The distillation residue is treated with hot xylene and the resulting xylene solution is allowed to cool to precipitate 5,7-dimethyl-2-(4'- cyanostyryl)-benzoxazole as yellow needle-like crystals. When recrystallized from ligroin containing benzene, slightly yellow needle-like crystals (M.P. 207209 C.) are obtained.

EXAMPLE 4 2-methyl-a-naphthoxazole (18.3 parts), benzaldehyde 11 parts) and zinc chloride (7 parts) are thoroughly mixed and are caused to react at l60200 C. for 8 hours with stirring. To the reaction product is added methanol of 3 times volume at hot state and after cooling the precipitate is filtered out. The precipitate is recrystallized from a mixture of ethanol and glacial acetic acid to give light yellow pillar-like crystals (M.P. 3 C.). This one is a double salt of 2-styryl-a-naphthoxazole and zinc chloride. On heating with water, 2-styryl-a-naphthoxazole is easily separated. Recrystallization from ligroin gives colorless needle-like crystals (M.P. 124-125 C.).

EXAM PLE Z-methyl-B-naphthoxazole (28 parts), 3-chlorobenzaldehyde (22 parts) and zinc chloride parts) are mixed and are caused to react at 160165 C. for 6 hours while the formed water is successively taken out of the reaction system. The reactants are dissolved in 150 parts of isopropanol. The isopropanol solution is allowed to cool to precipitate 2-(3'-chlorostyryl)-fl-naphthoxazole as yellow crystals. Recrystallization from methanol gives light yellow flake-like crystals (M.P. 114-115 C.).

EXAMPLE 6 Cinnamic acid (2'-oxynaphthyl-1') amide obtained from l-amino-Z-naphthol hydrochloric acid salt parts) and cinnamic acid chloride (17 parts) is boiled 10 with 10 parts of phosphor oxychloride in 50 parts of O- dichlorobenzene for 8 hours while water formed by the reaction is successively distilled out of the system. Then, O-dichlorobenzene is taken out b steam distillation and the distillation residue is treated with ligroin. The ligroin solution is allowed to cool to precipitate Z-Styryl-B-naphthoxazole as yellow crystals. Recrystallization from ligroin gives light yellow pillar-like crystals (M.P. 121.5423" C.).

EXAMPLE 7 One part of 2 (4'-cyanostyryl)-5,7-dimethylbenzoxazole of the following formula:

HHZW M on.

is thoroughly mixed with 9 parts of surface active agent of alkylbenzene sulfonic acid type to give a sample, and 0.2 part of the sample thus prepared per 10 parts of the polyester cloth to be treated is put into 400 parts of water to give a dispersed system. In this dispersed system the polyester cloth is treated at C. for 45 minutes. The treated cloth is washed with water and dried to give the remarkable brightening effect as compared with nontreated cloth.

What is claimed is:

1. A method for optical brightening of solid polymeric materials selected from the class consisting of polyesters, polyamides, acetalized polyvinyl alcohols, cellulose acetate and polyolefins, comprising treating said materials with an oxazole compound of the formula wherein A is a member selected from the group consisting of substituted benzene rings and an unsubstituted naphthalene ring, A being condensed with the oxazole ring, substituents of said benzene rings being selected from the group consisting of alkyl-, aryl-, and alkylenegroups and [when A is said unsubstituted naphthalene ring], R and R are selected from hydrogen, halogen, cyano group, carboxyl group and its ester residue, alkyl group and aryl group, [R being a cyano group when A is said benzene ring with R being selected as aforesaid,] said treating being effected by contacting the said materials with an aqueous dispersion containing said oxazole in an amount sufiicient to impart optical brightening effects to the material undergoing treatment.

2. A method as claimed in claim 1 wherein A of said formula is a benzene ring having at least one alkyl group as the substituent.

3. A method as claimed in claim 1 wherein the said compound is 5-methyl-2-(3'-chloro 4-cyanostyryl)-benzoxazole having the formula:

4. A method as claimed in claim 1 wherein the said compound is 5,7-dimethyl-2- 3'-chloro-4-cyanostyryl benzoxazole having the formula:

11 5. A method as claimed in claim 1 wherein the said compound is S-ethyl-Z-(3'-chlor0-4'-cyanostyryl)-benzoxazole having the formula:

6. A method as claimed in claim 1 wherein the said compound is S-methyl-Z-(4'-cyanostyryl)-benzoxazole having the formula:

\ -c11:110- CN Q 7. A method as claimed in claim 1 wherein the said compound is -methyl-2-(4'-carboxythoxystyryl)-benzoxazole havin the formula:

8. A method as claimed in claim 1 wherein A is a naphthalene ring.

9. A method as claimed in claim 1 wherein said compound is 2-(3'-chlorostyryl)-fl-naphthoxoazole having the formula:

10. A method as claimed in claim 1 wherein said compound is 2-(4'-chlorostyryl)-fi-naphthoxazole having the formula:

11. A method as claimed in claim 1 wherein said compound is 2-(3'-chlorostyryl)a-naphthoxazole having the formula:

l 2 12. A method as claimed in claim 1 wherein said compound is 2-(2'-chlorostyryl)-a-naphthoxazo1e having the formula:

13. A method as claimed in claim 1 wherein said compound is 2-(4-fluorostyryl)-fi-naphthoxazole having the formula:

16. A method as claimed in claim 1 wherein A is a benzene ring having an aryl group as the substituent.

17. A method as claimed in claim 1 wherein said compound is S-phenyl-Z-(4-cyanostyryl)-benzoxazo1e having the formula:

18. A method as claimed in claim 1 wherein said compound is 5-phenyl-2-styrylbenz/oxazole having the formula:

13 14 19. A method as claimed in claim 1 wherein said compound is Z-styryl-fi-naphthoxazole having the formula: Refemlces Clted o The following references, cited by the Examiner, are of record in the patented file of this patent or the original CCH=HC 5 patent. N UNITED STATES PATENTS 2,639,282 5/1953 Sprague et al. 260240.9X 3,120,520 2/1964 Buell l1733.5 3,158,610 11/1964 Buell 11733.5 1O 20. A method as claimed in claim 1 wherein said ma- FOREIGN PATENTS terial is an organic fibrous material. 569 402 4 1952 Great Britain 0 240 21. A method for optical brightening as claimed in 573,303 5/1959 Canada 260 240 claim 1 wherein the material treated is selected from the grboug colnsistinlg firlaaf polyester dfilzielr [prilyacrlyllrinfiitgile 15 WILLIAM D. MARTIN, Primary Examiner er p0 yam1 e er, aceta ize po in aco 0 er,

cellulose acetate fiber, and polyolefin hbe l'. DAVIS Asslstam Exammer 22. A method as claimed in claim 1 wherein A is a Us Cl X R substituted benzene ring.

23. A method as claimed in claim I wherein A is an 20 117-4383,

unsubstituted naphthalene ring. 

